The effects of epilepsy in sufferers vary widely, the only common feature being the occurrence of epileptic seizures, which are characterised by convulsions and, in severe cases, loss of consciousness. The frequency and severity of such occurrences varies very widely, however, as does the ability of sufferers voluntarily to control them, or to detect an impending occurrence.
The potential dangers of such occurrences have led to very substantial efforts being made to find a cure, or if not a cure then palliative or alleviative measures, for treating epilepsy, and there is a very substantial body of research which has been carried out, which has led to an ability to treat epilepsy in many sufferers, though the effectiveness of such treatment tends also to vary widely.
A large range of synthetic therapeutic drugs is available which affect epilepsy sufferers in different ways. In a substantial proportion of cases, improvements in the management of epilepsy for an individual patient can be achieved, but this tends to be accompanied by considerable side effects and accordingly drug-based management of epilepsy is not seen as a universally positive form of treatment. Indeed, around 30% of all epilepsy sufferers have a resistance to the drugs known for such treatment.
It has long been known that the occurrence of epileptic seizures, and their strength and frequency, correlate with mental state, and accordingly treatment programmes for an individual sufferer may well include mental training or conditioning as well as the physical administration of therapeutic drugs. A number of biofeedback approaches have been suggested for the management of epilepsy. These include different electroencephalographic (EEG) frequencies, cortical potentials and peripheral activity such as respiration (Sterman and Friar, 1972, Suppression of seizures in an epileptic following sensorimotor EEG feedback training. Electroenceph Clin Neurophysiology 33, 89-95; Sterman and McDonald, 1974, Biofeedback training of the sensorimotor electroencephalogram rhythm in man: Effects on epilepsy, Epilepsia 15, 395-416, Finley et al 1975 Reduction of seizures and normalisation of the EEG in severe epileptic following sensorimotor biofeedback training: Preliminary study. Biol. Psychol 2, 189-203; Lubar and Bahler, 1976, Behavioural management of epileptic seizures following EEG biofeedback training of the sensory motor rhythm. Biofeedback Self Regul. 1, 77-104, Fried et al, 1984, Behavioural control of intractable idiopathic seizures: 1. Self-regulation of end-tidal carbon dioxide. Psychosom Med 46, 315-31, Tozzo et al, 1988, EEG biofeedback and relaxation training in the control of epileptic seizures, Int J Psychophysiol 6, 185-94, Fried et al, 1990, Effect of diaphragmatic respiration with end-tidal CO2 biofeedback on respiration, EEG, and seizure frequency in idiopathic epilepsy, Ann NY Acad Sci 602, 67-96; Rockstroh et al, 1993, Cortical self-regulation in patients with epilepsy, Epilepsy Res 14, 63-72, Kotchoubey et al, 2001, Modification of slow cortical potentials in patients with refractory epilepsy: a controlled outcome study. Epilepsia 2001; 42: 406-16).
The following details of two investigations will illustrate the invention:
Pilot Clinical Trial
Three epilepsy sufferers were available, all experiencing at least two or three seizures a month, and having a history of no or poor response to anti-epileptic drug therapy, and who were not apparently suffering from mental illness.
Baseline seizure frequency was measured and recorded for three months. At the beginning of the fourth month, the three sufferers took part in biofeedback training sessions three times a week using apparatus as described in WO 93/02622, and with an animation sequence programmed into tho PC showing a fish swimming to left or right against a background scene. All three were asked by being alert to try to make the fish swim to the right, preferably without making physical movements, and without closing their eyes. The thrice-weekly sessions were carried out for four weeks and then discontinued. Throughout the time, and for the following three months, a record of seizure occurrences was kept for all three.
It was found that the seizure frequency was clearly reduced in the case of two of the three sufferers, though no significant change was found in the case of the third.
Wider Clinical Trial
This study sought to investigate the effects demonstrated by the pilot, but on a larger scale to provide same reliability. It was designed as a randomized control trial and carried out using the standard procedures for such trials. To start with, a group of drug refractory epilepsy sufferers was set up. The conditions of entry to the group were that the sufferer had to be between the ages of 16 and 60,to have suffered epileptic seizures for two years or more and at a rate of at least two to three seizures per month, and to have been on stable medication. Eighteen epilepsy sufferers who met these criteria were asked to participate in a seven month experiment to test a new treatment and, on giving informed consent, were randomly assigned to a group which was to receive actual GSR feedback and a group which was to act as a sham control group.
A preliminary analysis following the random allocation of the eighteen sufforers into a group of ten and a group of eight demonstrated that the two groups could be considered essentially identical, i.e. there was no statistically significant difference between the two groups, both showing a spread of age and severity and type of their epileptic condition.
Each of the participants kept a seizure diary for three months to establish baseline seizure frequency and then each was trained in biofeedback techniques (or exposed to sham biofeedback) over twelve sessions spread over a period of one month. The thrice-weekly sessions each lasted 30 minutes and in each case the sufferer was reminded of the task they were set, which was to make the computer-generated animation of a swimming fish move in a particular direction. In the case of ten of the sufferers, they were genuinely able to influence the movement of the fish on the screen by varying their alertness causing a change in GSR, this being achieved using a commercial biofeedback programme and its associated electrodes and sensors available commercially from Ultrasis UK Limited under the designation Inner Tuner.
Those of the other group in the sham control group were given the same instructions as those in the other group, but the screen display shown to each of them was a pre-recorded animation sequence where the movement of the fish was random. None of the sufferers in the sham control group gave any indication of realizing that they were in that group, although none actually experienced any reduction in seizure frequency during the period of the twelve sessions. In contrast, six of the ten sufferers in the group exposed to genuine biofeedback experienced a reduction in seizure frequency before the end of the twelve sessions to 50% or less of their baseline frequency.
Thereafter, all 18 sufferers kept a seizure diary for a further three months and, at the end of that period, the data was collected from the diaries and analysed.
On analysing the data at the end of the seven month trial, there was a substantial difference in seizure reduction between the groups. In the group which received genuine biofeedback, there was a statistically significant decrease in seizure frequency. Of the ten patients in that group, six showed more than a 50% reduction in seizure frequency, the mean percentage change being −49.26%. Two patients even became virtually seizure free.
In contrast, in the sham control group of eight patients, there was no statistically significant reduction in the seizure frequency. These results are shown graphically in FIG. 1.
It is particularly noteworthy that, in the case of six of the individuals, there was a good response to treatment over the seven month period and this is shown in FIGS. 2-7.